People with lower back and leg pain may often hear the word 'sciatica'. Words are often heard, but most people have only a partial understanding of them, and some may even be completely wrong. In fact, sciatica is a symptom of a group of diseases, rather than a specific disease. Today, the pain doctor will take you to understand this kind of "sitting and standing difficult" pain! Sciatica is more than just pain. "Sciatica" is a type of pain transmitted along the pathway of the sciatic nerve due to compression of the nerve root, radiating from the lumbosacral region through the buttocks to the lower limbs and even to the lower legs and ankles. The following are common symptoms of sciatica: Radiation pain can be paroxysmal or persistent, and this type of pain usually affects only one leg or may develop to both legs. Coughing or sneezing may worsen when you sit, stand, or walk. Leg numbness: The affected limb often has numbness and decreased sensation on the outer side of the lower leg and the dorsum of the foot, relaxation of gluteus muscle tension, weakened extensor and flexor muscles, and weakened or disappeared Achilles tendon reflexes. The worsening of pain symptoms and increased numbness in the limbs, as well as the gradual atrophy of muscles below the buttocks, result in a decrease in mobility. The four diseases are all caused by sciatica caused by lumbar disc herniation. After the lumbar disc herniation, it compresses the nearby sciatic nerve, causing sciatica, and then causing symptoms such as pain in the buttocks, back of the thighs, and outer side of the lower legs, or radiation pain, as well as lumbar muscle spasms and limited lumbar mobility. The sciatica caused by lumbar spinal stenosis may come from intervertebral disc herniation and calcification of bone and ligaments in the spinal canal, as well as from spinal spondylolisthesis, small joint hyperplasia, and intervertebral foramen stenosis caused by trauma, resulting in narrowing of the spinal canal and nerve roots, narrowing of the nerve pathway, and sciatica caused by nerve root stimulation or compression. The typical symptom is sciatica that radiates along the direction of the sciatic nerve to the legs after walking for a period of time, gradually worsening. However, the symptoms decrease or disappear after bending down or resting, which is called "intermittent claudication". Piriformis syndrome causes sciatica. The piriformis muscle is a spindle shaped muscle located in the center of the buttocks, and the sciatic nerve passes through or passes through this muscle. When there is a problem with this muscle, it can cause stimulation of the sciatic nerve, causing hip pain accompanied by lower limb pain and numbness, which is called piriformis syndrome. The causes of this disease include: long-term sedentary individuals, such as office workers, who experience muscle stiffness and inactivation due to prolonged sitting; Poor postures such as pelvic tilt and cross legged posture result in imbalanced muscle strength on the left and right sides; Injury caused by sudden exercise without warm-up before exercise; Excessive exercise (running, etc.) leads to excessive use of the piriformis muscle. Sciatica caused by lumbosacral radiculitis caused by various reasons. Lumbosacral radiculitis can arise from pelvic inflammation, tumors, or postoperative adhesions, as well as from neurodegeneration caused by autoimmune diseases. The onset is generally acute, and the damage often extends beyond the area innervated by the sciatic nerve, manifested as weakness, pain, and mild muscle atrophy in the entire lower limb. In addition, the Achilles tendon reflex and knee tendon reflex are also often reduced